Ball valve

ABSTRACT

The disclosed embodiments include ball valves having integrated seats. The integrated seats are included in a ball body assembly of a valve body. The ball body assembly may rotate with respect to the valve body to open or close the valve. The integrated seats may contact walls of a bore to sealingly close the valve.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional PatentApplication No. 14/555,625, entitled “Ball Valve”, filed on Nov. 27,2014, which is herein incorporated by reference in its entirety, whichis a continuation of U.S. Non-Provisional patent application Ser. No.13/975,319, entitled “Ball Valve”, filed on Aug. 24, 2013, now U.S. Pat.No. 8,960,642, issued on Feb. 24, 2015, which is herein incorporated byreference in its entirety, which is a continuation of U.S.Non-Provisional patent application Ser. No. 13/315,233, entitled “BallValve”, filed on Dec. 8, 2011, now U.S. Pat. No. 8,727,314, issued onMay 20, 2014, which is herein incorporated by reference in its entirety,and which claims priority to and benefit of EP Patent Application No.10306377.2, entitled “BALL VALVE”, filed Dec. 8, 2010, which is hereinincorporated by reference in its entirety.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present invention,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentinvention. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

Ball valves are capable of controlling a flow through a conduit by usinga sphere with a port or hole typically centered in the sphere. The valveis opened by rotating the sphere so as to position the port or hole inline with both ends of the valve. A flow may thus move from a first endof the valve, traverse the port or hole, and continue through the secondend of the valve. Likewise, the valve is closed by rotating the sphereso as to position the port or hole perpendicular to the ends of thevalve. Unfortunately, the sphere may deform over time under loadingconditions, resulting in leakage or improper seals.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features, aspects, and advantages of the present invention willbecome better understood when the following detailed description is readwith reference to the accompanying figures in which like charactersrepresent like parts throughout the figures, wherein:

FIG. 1 is a perspective view of a ball valve and valve actuators inaccordance with an embodiment of the disclosure;

FIG. 2 is an exploded perspective side view of a trunnion ball valve,including flanged valve ends, a valve body, and a ball body assembly inaccordance with an embodiment of the disclosure;

FIG. 3 is an exploded perspective side-view of components of a ballvalve in accordance with an embodiment of the disclosure;

FIG. 4 is a cross-sectional view of a ball valve in accordance with anembodiment of the disclosure;

FIG. 5 is a partial cross-sectional view of an annular integrated seatin accordance with an embodiment of the disclosure; and

FIG. 6 is a cross-sectional side view of an embodiment of a double blockand bleed valve.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present invention will bedescribed below. These described embodiments are only exemplary of thepresent invention. Additionally, in an effort to provide a concisedescription of these exemplary embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the presentinvention, the articles “a,” “an,” “the,” and “said” are intended tomean that there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.Moreover, the use of “top,” “bottom,” “above,” “below,” and variationsof these terms is made for convenience, but does not require anyparticular orientation of the components.

The disclosed embodiments include a ball valve, such as a trunnion ballvalve, having a valve seat integrated in the ball body capable ofreducing or eliminating leakage through the bore-to-seat interface. Thevalve seat is disposed in the ball body and includes a geometry and“piston effect” techniques suitable for sealingly maintaining contactwith the bore, even in situations where the ball body is not completelyspherical. Additionally, a substantial portion of the ball body may beleft “raw” or unfinished with only the seal and trim areas machined,thus saving time and costs of manufacture. The ball valve may be usedwith piping of different sizes (e.g., approximately between 1/2 in. to30 in., 15 in. to 45 in., 35 in. to 80 in. diameters) and different flowpressures (e.g., approximately between 5-50,000 PSI). Further, the ballvalve is capable of reducing actuation torque due to a reduced pistoneffect. Additionally, the integrated seat techniques disclosed hereinenable a compact ball valve design suitable for improved installationand maintenance. Indeed, the compact ball valve design eliminates theneed for the use of special tools and techniques, such as retractingseat tools and/or sophisticated multiple sealing elements used whenservicing traditional ball valves.

FIG. 1 is a perspective side view of embodiments of a trunnion ballvalve 10, a paddle actuator 12, a manual actuator 14, and a hydraulicactuator 16. A trunnion or stem 18 of the trunnion ball valve 10 may beconnected to any of the actuators 12, 14, or 16 and used to open andclose the ball valve by applying a torque. For example, the paddleactuator 12 may be connected for subsea applications and used by aremotely operated underwater vehicle (ROV). The ROV may rotate thepaddle and thus open or close the ball valve 10. Likewise, the manualactuator 14 may be connected and used for above-ground applications. Ahuman operator may turn the wheel 20 of the manual actuator, thusopening or closing the ball valve 10. Further, the hydraulic actuator 16may be used for remote valve activation. Accordingly, the ball valve 10may be remotely opened or closed by remote hydraulic (or electric)actuation. Actuation torque for the ball valve 10 may be reduced byusing certain embodiments disclosed herein, such as ball body integratedseats, while enabling the use of higher working pressures.

In the illustrated embodiment, the trunnion ball valve 10 includes avalve body 22 having a length L1. The valve body 22 may be attached to aset of flanged valve ends 24 and 26, as illustrated. In certainapplications, such as applications specifying quick removal andreplacement of a valve, the flanged valve ends 24 and 26 may be used tosecurely connect the valve body 22 to conduit or pipe. The flanged valveends 24 and 26 enable easy installation and removal of the ball valve 10from a conduit such as a flanged pipe. The ball valve 10 may beinstalled, for example, by using gaskets and a plurality of nuts andbolts suitable for securing the flanged valve ends 24 and 26 to theconduit. In other applications, such as subsea manifold applications, itmay be desirable to fixedly couple the ball valve 10 to the conduit, byusing welds. Welding the ball valve 10 to the conduit may reduce weight,create stronger connections, and define a substantially leak-proofpassage. Accordingly, the flanged valve ends 24 and 26 may be replacedwith a set of weldable valve ends (not shown). Indeed, the use of thecertain embodiments described herein, such as integrated seats disposedin a ball body, allow for the use of welding heat without damage to thevalve's component parts. The weldable valve ends are capable ofwithstanding the heat generated during welding and may be capable ofmeeting ISO 14313 (pipeline valves) and ISO 14723 (subsea pipelinevalves) specifications. Indeed, the trunnion valve 10 may be capable ofmeeting a variety of valve-related ISO, ANSI, API, ASME, and/or NACEspecifications, including subsea specifications. Further, it is to beunderstood that other valve ends may be used, including combinations offlanged valve ends, weldable valve ends, and/or hub valve ends. That is,the valve body 22 may include a flange valve end 24 at one end of thevalve body 22 and a hub valve end at the opposite end.

FIG. 2 depicts an exploded perspective view of the trunnion ball valve10 of FIG. 1, illustrating details of the flanged valve ends 24 and 26,the valve body 22, and a ball body assembly 28. The ball body assembly28 is configured to enable a flow 30 in an axial direction. The flow 30may be driven, for example, by a pump, a compressor, a well pressure, orany other device capable of creating a movement of a fluid through afluid passage 32 defined by the internal walls of the valve body 22. Inthe depicted embodiment, the ball body assembly 28 includes a ball body34 having a passage 36, e.g., an approximately circular opening 36. Theball body assembly 28 may be disposed inside of the valve body 22 androtated relative to the valve body 22 so as to open and close the fluidpassage 32. Indeed, the rotation of the ball body assembly 28 results inan equivalent rotation of the circular opening 36, thus allowing theflow 30 to enter inwardly into the valve body 22 through one side 31 ofthe valve body 22, traverse the opening 36 and continue exitingoutwardly through the opposite side 33 of the valve body 22. The flow 30may enter through either of the two sides 31, 33 of the valve body 22and exit through the opposite side.

In the depicted embodiment, the trunnion ball valve 10 includes theflanged valve ends 24 and 26, which may be secured concentrically orco-axially with respect to the valve body 22 as shown in FIG. 1.Accordingly, the flow 30 may enter the flanged valve end 24 (or 26) intothe valve body 22, traverse through the opening 36, and exit through theflange 26 (or 24). In certain embodiments, the flange valve ends 24 and26 may include contact surfaces or walls suitable for engaging a seat38, such as a toroidal or annular seat 38. The annular seat 38 isintegrated into the ball body assembly 28 and includes, in certainembodiments, “piston effect” features that enable a more secure sealingof the ball body assembly 28, even in situations where the ball body 34may not be completely spherical. For example, the piston effect featuresmay include one or more chambers suitable for using the fluid flow 30 tobias the annular seat 38 against the direction of flow. Indeed, the seat38 allows for the ball body 34 to undergo certain deformation, while theseat 38 maintains a suitable seal against the flow 30 of fluid.

The seat 38 enables operation of the valve 10 at higher flow pressures,such as pressures approximately between 5-50,000 PSI, and piping sizesof approximately between 1/2 in. to 30 in., 15 in. to 45 in., 35 in. to80 in. Such high pressure, high flow conditions may result in ball bodydeformations with a corresponding seal leakage in traditional ballvalves that do not incorporate the integrated seat 38. This leakage issubstantially reduced or eliminated by using the integrated seat 38.Indeed, the embodiments disclosed herein enable a substantialimprovement in maintaining a suitable seal even in circumstances wherethe ball body 34 experiences higher pressures and/or higher flow rates,because most resulting deformations may occur near the stem 18 area ofthe ball body assembly 28, which is independent from the integrated seat38.

In certain embodiments, the valve body 22 may allow for improvedmaintenance and/or manufacturing access by including a top entry opening37 suitable for inserting the ball body assembly 28 into the valve body22. Traditionally, special tools and/or multiple sealing elements mayhave been needed to remove and replace the ball body 34, for example,because of spring-loaded seats disposed inside a bore 40 of the valveend 24 and on a bore 42 of the valve end 26. Such bore-mounted seats maynow be replaced with the integrated seats 38 on the ball body assembly28. Accordingly, the ball body assembly 28 may be removed and/orinserted in a ball open position into the valve body 22 without the needfor special tools and/or sealing elements. Indeed, the use of theintegrated seats 38 on the ball body assembly 28, as described in moredetail below with respect to FIG. 3, enables a more easily maintainableand compact ball valve 10.

FIG. 3 is an exploded perspective side view of an embodiment of the ballbody assembly 28. In the depicted embodiment, the ball body assembly 28,includes the ball body 34 having grooves 44 (e.g., annular grooves) on afirst side 31 of the ball body 34. The grooves 44 may be milled ormachined to form smooth surfaces. The grooves 44 are configured toengage an seal 46, a spring 48, a seat ring or washer 50, and theannular seat 38. A second annular seat 38, with corresponding grooves44, seal 46, spring 48, and seat ring 50, is disposed on a second side33 of the ball body 34 opposite from the seat 38 on the first side 31.The use of the integrated seats 38 facilitates an improved seal in amore compact ball valve 10 suitable for enabling high pressure flows.

In certain embodiments, manufacturing time and cost may be reduced byleaving most of the ball body 34 unfinished or “raw.” That is, the ballbody 34 may be cast, but only certain areas of the ball body, such asthe areas near or on the grooves 44, may be further treated throughmachining, milling, and/or the application of a coating. The remainderof the ball body 34 may not come into sealing contact with other valve10 components, and thus, all ball body areas may not require furthertreatment and/or coating. It is to be understood that, in otherembodiments, other areas of the ball body 34 may receive furthertreatment, including milling, machining, and/or coating.

In the depicted embodiment, the seal 46 is disposed first onto thegrooves 44. The seal 46 may enable an improved seal between the seat 38and the ball body 34. Accordingly, the seal 46 may be an elastomericseal, a plastic seal, a graphite seal, or manufactured out of any othersuitable material. The spring 48 may then be disposed onto the grooves44. The spring 48 enables a compressive force between the seat 38 andthe ball body 34 that may “push” the seat 38 outwardly away from theball body 34, as described in more detail below with respect to FIG. 4.The spring 48 may thus aid in an enhanced contact betweenoutwardly-facing walls 52 of the seat 38 and certain walls inside thebores 40 and 42 of the ends 24 and 26. In certain embodiments, theoutwardly-facing walls 52 may be coated so as to reduce contact frictionand to aid in corrosion resistance. For example, the outwardly-facingwalls 52 may be coated with carbide-based coatings, such as a tungstencarbide coating (TCC), a boron carbide coating, or any other suitablecoating. The seat ring 50 may be disposed between the seat 38 and thespring 48. The seat ring 50 may be used to limit seat 38 displacementand to maintain spring 48 compressive force. The seat ring 50 may alsobe provided in different thicknesses and may be used to fine tune theball valve 10 for different operational environments.

Thicker seat rings 50 may allow for an increased distance of the seat 38outwardly from the ball body 34, thus increasing the contact surfaceand/or contact force between the seat 38 and certain walls of the valveends 24 and 26. Similarly, slimmer seat rings 50 may allow for adecreased distance of the seat 38 outwardly from the ball body 34, thusdecreasing the contact surface and/or contact force between the seat 38and certain walls of the valve end 24. Likewise, the spring 48 may beprovided with different spring forces suitable for increasing ordecreasing the outward bias of the seat 38 due to the spring 48. Incertain embodiments, the spring 48 force may be used only to initiate apressure build up, and the spring 48 force may be a constant value for agiven size of valve 10. Accordingly, the ball valve 10 may be fine tunedto provide sealing forces suitable for numerous operationalenvironments, such as low pressure environments, medium pressureenvironments, and high pressure environments. In certain embodiments,the seat 38 may include “piston effect” features, such as described inmore detail below with respect to FIG. 4. The piston effect features maybe configured to enable operation of the ball valve 10 with sufficientsealing in a variety of operational environments. Indeed, the “pistoneffect” could be tailored to operate in high pressure applications.

FIG. 4 is a cross-sectional view of an embodiment of the trunnion ballvalve 10 in a fully closed position. As illustrated, the annularintegrated seat 38 on the first side 31 is spring biased against a wall54, and the annular integrated seat 38 on the second side 33 is springbiased against a wall 56. In certain embodiments, the annular seats 38enable a metal-to-metal contact with the walls 54 and 56. Themetal-to-metal seating may be useful in applications, such as hightemperature applications and/or corrosive fluid applications.Accordingly, the annular seats 38 and the walls 54 and 56 may bemanufactured out of a metal and/or a metal alloy, such as inconel,stainless steel, cro-moly, steel, and so forth. Additionally, the seats38 and/or the walls 54 and 56 may be coated (e.g., TCC coated) to reducefriction and improve resistance to corrosion.

In other embodiments, the seats 38 and 39 may enable a “soft seal,” suchas an elastomer-to-metal or elastomer-to-elastomer contact. Accordingly,the seats 38 and 39, and/or the walls 54 and 56, may include elastomerinserts or may be manufactured out of elastomer materials such asthermoplastics, synthetic rubber, polymers, or other non metallicsealing materials. Such “soft seal” embodiments, for example, may aid inpreventing electrolysis between the contact points should the valve beleft in a closed position for prolonged periods of time. It is to beunderstood that, in other embodiments, the seats 38 and 39 may contact awall of the valve body 22 instead of the walls 54 and 56 of the valveends 24 and 26. Indeed, walls of the valve body 22 may be used to sealthe fluid passage 32.

The use of the annular seats 38 results in a more compact ball valve 10.For example, the ball body 34 may be substantially the same length L1 asthe ball body assembly 28. Additionally, the valve ends 24 and 26 maynot require the use of a bore seat. The bore seat typically wouldrequire additional space because it is separate from the ball body 34.Instead, the valve ends 24 and 26 may directly contact the integratedseats 38 on the ball body 34. Such an embodiment results in a morecompact ball valve 10 having improved sealing capabilities. The valve 10may also include a top entry component 58 disposed in the valve body 22,suitable for in-line maintenance. More specifically, the top entrycomponent 58 may be removed, while the remaining components of the valve10 remain coupled to a conduit 60 (i.e., in-line with the conduit 60).When the top entry component 58 is removed, the ball body assembly 28components can be inspected, and a maintenance may be performed. Forexample, components of the ball valve 10 may be replaced, including theseats 38.

Embodiments of the trunnion ball valve 10 may also include “pistoneffect” features in which the flow pressure aids in maintaining a securesealing contact between the seats 38 and the walls 54 and 56. In asingle piston effect embodiment, the trunnion ball valve 10 is designedto use the fluid pressure to further aid in sealing the seat 38 on thefirst side 31 and/or the second side 33. For example, a fluid flow 62may enter the bore 40 and impinge upon the ball body 34. The fluid flow62 may result in a pressure against the ball body 34. Such a pressuremay move the ball body 34 in a downstream fluid 62 direction, biasingthe downstream seat 38 more firmly against the wall 56 of the valve end26. Indeed, increasing the fluid flow pressure may correspondinglyincrease the piston effect pressure against the ball body 34, thusresulting in a more secure seal of the seat 38. Likewise, a fluid flow64 may enter the bore 42 and impinge upon the ball body 34, resulting ina fluid pressure against the ball body 34. The pressure may move theball body 34 in a downstream fluid 64 direction, biasing the downstreamseat 38 more firmly against the wall 54 of the valve end 24.

FIG. 5 is a partial cross-sectional view of an embodiment of theintegrated seat 38 depicted in FIG. 4 taken within line 5-5. In a doublepiston effect embodiment, the trunnion ball valve 10 is designed to usefluid pressure to further aid in sealing both of the two annular seats38. As mentioned above with respect to FIG. 4, the fluid flow 62entering the bore 40 may result in a pressure suitable for biasing theseat 38 more firmly against the wall 56. This same fluid flow 62 mayalso result in a pressure suitable for biasing the seat 38 more firmlyagainst the wall 54 of the valve end 24. Accordingly, the fluid flow 62may enter the bore 40 and flow into a chamber 66 of the ball body 34 anda chamber 68 of the integrated seat 38. The fluid pressure resultingfrom the fluid flow 62 entering the chambers 66 and 68 may move or pushthe seat 38 outwardly towards the wall 54. Indeed, further increase influid pressure may result in a corresponding increase in the force ofthe contact between the upstream seat 38 and the wall 54. As the seat 38moves, the seal 46 may aid in maintaining a secure seal downstream ofthe fluid flow 62. Additionally, the spring 48 may also aid in movingthe seat 38 outwardly from the ball body 34. Further, because the seat38 is independent of the ball body 34, the seal or contact between theseat 38 and the wall 54 may be maintained even if the ball body 34 movesdownstream of the fluid 62 and/or undergoes deformation. Indeed, theball body 34 may not need to be approximately spherical shape in orderfor the ball valve 10 to maintain a secure seal. Accordingly, the doublepiston effect is capable of using the fluid 62 pressure to aid insealing the seats 38 on both sides 31 and 33.

FIG. 6 is a cross-sectional view of an embodiment of a multiple ballassembly valve, such as a double block and bleed valve 70, whichincludes two ball body assemblies 72 and 74. More specifically, the ballbody assembly 72 includes annular integrated seats 76 and 78, while theball body assembly 74 includes annular integrated seats 80 and 82.Indeed, the integrated seats 76, 78, 80, and 82 allow for themanufacturing of compact valves having two (or more) ball bodyassemblies 72 and 74. In the depicted embodiment, the use of the twoball body assemblies 72 and 74 provides for dual isolation of a flow.For example, the first ball body assembly 72 may be used to stop a fluidflow 83, while maintenance activities are carried out in the second ballbody assembly 74. Indeed, each of the ball body assemblies 72 and 74 iscapable of isolating a fluid flow from the other assembly. The depicteddouble block and bleed valve 70 may be made more compact because theintegrated seats 76, 78, 80, and 82 are designed to operate withingrooves in the ball assemblies 72 and 74, and thus, the valve 70 may notrequire seats in the valve ends 84 and 86. Accordingly, space that wouldhave been used to add seats on the valve ends 84 and 86 may beeliminated, resulting in a more compact double block and bleed valve 70.The ball body assemblies 72 and 74, including integrated seats 76, 78,80, and 82, may be functionally similar to the single ball assembly 28having the integrated seats 38 but may have different sizes and orshapes to more suitably operate in a valve body 88.

More specifically, a stem 90 may be used to actuate the ball bodyassembly 72 by rotating the ball body assembly 72 with respect to thevalve body 88. Likewise, a stem 92 may be used to actuate the ball bodyassembly 74 by rotating the ball body assembly 74 with respect to thevalve body 88. In a closed valve position, the integrated seat 76contacts walls of a bore 96 of the valve end 84. Additionally, in aclosed valve position, the integrated seat 78 contacts walls of thevalve body 88. Likewise, in a closed valve position, the integrated seat80 contacts walls of the valve body 88. Additionally, in a closed valveposition, the integrated seat 82 contacts walls of a bore 98 of thevalve end 86. Indeed, the disclosed embodiments enable a dual flowisolation suitable for performing in-line valve maintenance of either ofthe ball body assemblies 72 or 74, while the other assembly is used tostop a flow.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

1-20. (canceled)
 21. A system, comprising: a valve assembly, comprising:a valve body having a fluid passage; a body assembly disposed in thevalve body along the fluid passage, wherein the body assembly comprises:a body having a first groove; a first seat disposed in the first groove;and a first spring disposed in the first groove, wherein the firstspring is configured to bias the first seat away from the body toward afirst seating portion of the valve body.
 22. The system of claim 21,comprising a first seal disposed in the first groove separate from thefirst spring.
 23. The system of claim 21, wherein the first springcomprises a plurality of curved portions.
 24. The system of claim 21,wherein the first spring has a thickness that extends into at least aportion of a depth of the first groove, and the first spring has one ormore spaces in the thickness of the first spring.
 25. The system ofclaim 21, wherein the first seat comprises a first annular seat having afirst central opening.
 26. The system of claim 25, wherein the firstgroove comprises a first annular groove disposed about a first portionof the body, and the first annular seat is disposed in the first annulargroove with the first central opening disposed about the first portionof the body.
 27. The system of claim 26, wherein the first spring isdisposed in the first annular groove with a central opening disposedabout the first portion of the body.
 28. The system of claim 21, whereinthe first spring is configured to move the first seat away from the bodyover a range of movement.
 29. The system of claim 28, wherein the valveassembly is configured to limit displacement of the first seat.
 30. Thesystem of claim 21, wherein the first seat comprises an L-shapedcross-section.
 31. The system of claim 21, wherein the first groove andthe first seat are oriented substantially perpendicular to an axis ofthe fluid passage.
 32. The system of claim 21, wherein the body assemblyis configured to rotate about a rotational axis between an open positionand a closed position relative to the fluid passage.
 33. The system ofclaim 32, wherein the body of the body assembly comprises an opening,the body assembly is configured to position the opening into the fluidpassage in the open position, and the body assembly is configured toposition the opening out of the fluid passage in the closed position.34. The system of claim 21, wherein the body of the body assembly is atleast partially ball shaped.
 35. The system of claim 21, wherein thebody of the body assembly is substantially ball shaped between oppositefirst and second stem portions.
 36. The system of claim 21, wherein thebody assembly comprises: a second seat disposed in a second groove inthe body; and a second spring disposed in the second groove, wherein thesecond spring is configured to bias the second seat away from the bodytoward a second seating portion of the valve body.
 37. The system ofclaim 21, comprising a first fluid chamber disposed in the first groove,wherein the first fluid chamber is configured to use fluid pressure tobias the first seat away from the body toward the first seating portionof the valve body.
 38. A system, comprising: a body assembly configuredto mount in a valve body along a fluid passage, wherein the bodyassembly comprises: a body having a first groove; a first seat disposedin the first groove; and a first spring disposed in the first groove,wherein the first spring is configured to bias the first seat away fromthe body toward a first seating portion of the valve body.
 39. Thesystem of claim 38, wherein the body of the body assembly comprises anopening, and the body of the body assembly is at least partially ballshaped.
 40. The system of claim 38, wherein the first spring is notconfigured to seal.
 41. A method, comprising: seating a body assembly ina valve body along a fluid passage with a first seat disposed in a firstgroove of a body of the body assembly; and biasing the first seat awayfrom the body toward a first seating portion of the valve body with afirst spring disposed in the first groove.